cannot write with X-HEEP on FLASH into the data_flash_only section

[davideschiavone]

When mapping data to the X-HEEP data_flash_only section as in this example, the test fails as the values read back are all 0s.

By adding printf here and there in iceprog, I could see data being written correctly from the compiled .hex file.
Even when such .hex file gets modified by hand.

I noticed that the data written are above the file_size, as this does not take into account gaps into the address space.
by adding a "+1" here

for (int addr = begin_addr; addr < end_addr+1; addr += block_size) {

I erased one extra 64KB block to be sure to erase also data above the address that I wanted to write.

The values are mapped at address 0x10000, and printf into the flash_prog functions show that data are written as expected, and printf in the flash_read functions confirm that the data read are correct.

When running on X-HEEP instead, prinft into the bsp functions show that the address and data written are correct, but when reading, only values equal to 0 are read, failing the test.

Possible bugs are in SW, but I could not identify where (yet).